1. Field of the Invention
The present invention pertains to a bulk material loader that directs material onto a conveying surface of a belt conveyor. In particular, the present invention is a material loader that has a retractable and extendable tubular length where the length of the loader is extended to direct material through the loader onto the moving belt surface of a conveyor, and the length of the loader is retracted when the loader is not directing material onto the conveyor to provide adequate clearance for material loaded onto the conveyor by another loader located upstream of the conveyor.
2. Description of the Related Art
The transporting of bulk material, for example coal, from one area to another often involves the transfer of a stream or flow of the material from two or more conveyors onto another, single conveyor. In the transfer of the material from one conveyor to a second conveyor, it is often necessary that the material be discharged from the first conveyor into a tubular loader. The material falls through the tubular loader and is directed by the loader onto the conveying surface of the second conveyor. The bulk material exits a bottom opening of the tubular loader and impacts with the moving conveying surface of the second conveyor.
The conveying surface of the second conveyor is often moving at a slower speed than the speed of the bulk material falling through the loader. The faster speed of the material impacting the conveying surface can result in spillage of the bulk material from the sides of the conveying surface. To reduce the amount of spillage, it is desirable that the exit opening or bottom opening of the tubular loader be positioned in close proximity to the conveying surface so that the material exiting the bottom opening has a minimum amount of undirected free-fall to the conveying surface.
The need to position the bottom exit opening of the tubular loader in close proximity to the conveying surface presents problems when two or more conveyors discharge bulk material to two or more tubular loaders that direct the material to a single receiving conveyor. The two loaders are positioned along the length of the receiving conveyor with the first of the loaders positioned toward the upstream end of the receiving conveyor and the second of the loaders positioned in the downstream direction of the receiving conveyor from the first loader. The two discharging conveyors are typically alternately operated so that only one conveyor at a time is discharging bulk material to one of the two loaders, and the one loader is directing the material onto the receiving conveyor. With this arrangement, it is possible to position the bottom outlet opening of the first, upstream loader in close proximity to the conveying surface of the conveyor. However, the bottom, outlet opening of the second, downstream loader cannot be positioned in close proximity to the conveying surface of the receiving conveyor without coming into contact with material loaded onto the conveying surface by the upstream loader. The bottom, outlet opening of the second, downstream loader must be positioned higher above the conveying surface of the receiving conveyor than the bottom, outlet opening of the first, upstream loader in order to provide adequate clearance for the material loaded onto the conveying surface by the first, upstream loader to pass beneath the bottom outlet opening of the second, downstream loader. The need to position the bottom outlet opening of the second, downstream loader at a higher position above the conveying surface presents the problem of increased spillage of the bulk material directed through the second, downstream loader onto the conveying surface.